CN113897913A

CN113897913A - Arch dam mass concrete crack control method

Info

Publication number: CN113897913A
Application number: CN202111118891.7A
Authority: CN
Inventors: 孟天琦; 罗卫群; 张修凯
Original assignee: Shandong Water Conservancy Group Co ltd
Current assignee: Shandong Water Conservancy Group Co ltd
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2022-01-07
Anticipated expiration: 2041-09-24
Also published as: CN113897913B

Abstract

The application relates to the field of concrete construction technology, in particular to a method for controlling large-volume concrete cracks of an arch dam, which comprises the following steps: erecting a template according to design requirements; binding reinforcing steel bars, namely binding the reinforcing steel bars required in the large-volume concrete according to design requirements; installing heat exhaust pipelines, fixing a plurality of heat exhaust pipelines on the reinforcing steel bars in parallel, and exposing the end heads of the heat exhaust pipelines out of the concrete surface; pouring concrete, pumping the concrete into the template, and vibrating to compact; maintaining, covering the heat insulation layer, and injecting water into the heat exhaust pipeline; plugging the heat exhaust pipeline, and injecting cement mortar into the heat exhaust pipeline; the heat exhaust pipeline comprises a main pipe, a connecting pipe and an auxiliary pipe. This application has the effect that improves dam bulky concrete and produces the crack problem.

Description

Arch dam mass concrete crack control method

Technical Field

The application relates to the field of concrete construction technology, in particular to a method for controlling a large-volume concrete crack of an arch dam.

Background

The mass concrete generally refers to mass concrete with the minimum physical dimension of a concrete structure not less than 1m, or concrete which is expected to cause harmful crack generation due to temperature change and shrinkage caused by hydration of a cementing material in the concrete.

One common problem in the construction of mass concrete is concrete cracking, and the causes of concrete cracking are many, and the main one is hydration heat. In the hydration process of cement, after chemical reaction, a large amount of heat can be generated, and because the surface coefficient of a concrete structure is small, when the hydration heat of the cement is continuously generated, a large amount of heat is accumulated in the concrete, and because the heat dissipation speed is far less than the heat generation speed of the hydration heat, the temperature difference in the concrete is gradually changed, and cracks are generated. In important infrastructures such as arch dams and the like, the concrete crack control requirements are more strict.

At present, the concrete cracks are mostly controlled by adopting a method of cooling the interior of concrete, namely, a heat exhaust pipeline is pre-embedded in the concrete, then continuous ventilation or water is supplied to the heat exhaust pipeline, and air or water is used as a medium to take away heat in the concrete.

In view of the above-mentioned related technologies, the inventor believes that the dam body is generally large in size, and the number and spatial arrangement of the pre-buried pipelines are influenced by factors such as dam body strength design requirements, so that the heat exhaust pipelines cannot be densely distributed with dam body concrete, concrete far away from the heat exhaust pipelines is still greatly influenced by hydration heat, and the possibility of generating cracks is still likely to exist in these places.

Disclosure of Invention

In order to solve the problem that large-volume concrete of a dam cracks, the application provides a crack control method for the large-volume concrete of the arch dam.

The application provides a method for controlling large-volume concrete cracks of an arch dam, which adopts the following technical scheme:

a method for controlling large-volume concrete cracks of an arch dam comprises the following steps:

erecting a template according to design requirements;

binding reinforcing steel bars, namely binding the reinforcing steel bars required in the large-volume concrete according to design requirements;

installing heat exhaust pipelines, fixing a plurality of heat exhaust pipelines on the reinforcing steel bars in parallel, and exposing the end heads of the heat exhaust pipelines out of the concrete surface;

pouring concrete, pumping the concrete into the template, and vibrating to compact;

maintaining, covering the heat insulation layer, and injecting water into the heat exhaust pipeline;

plugging the heat exhaust pipeline, and injecting cement mortar into the heat exhaust pipeline;

the heat exhaust pipeline comprises a main pipe, a connecting pipe and an auxiliary pipe; the person in charge is provided with a plurality ofly, every the person in charge includes a plurality of main tube joints, the connecting pipe is installed between two adjacent main tube joints, be provided with two sets of through-holes along self length direction on the connecting pipe perisporium, every group includes a plurality of through-hole, the position that the connecting pipe perisporium corresponds the through-hole is equipped with the connector, the auxiliary pipe is provided with a plurality ofly, the auxiliary pipe is connected between two connectors that are located different groups, the auxiliary pipe is the arc and is fixed in on the reinforcing bar.

By adopting the technical scheme, after being injected into the heat exhaust pipeline, water enters the auxiliary pipe through the main pipe, hydration heat in the concrete is absorbed by the auxiliary pipe distributed in the concrete, and the heat carried by the water is finally exhausted from the main pipe, so that the heat in the concrete is reduced; the heat preservation layer covers the surface of the concrete, the heat loss of the surface of the concrete is delayed, and the temperature difference between the inside and the outside of the concrete is reduced in a mode of internal accelerated cooling and external delayed cooling; compared with the related art, the method for controlling the cracks of the large-volume concrete of the arch dam can effectively solve the problem that the cracks are generated in the large-volume concrete of the dam.

Optionally, a guide hopper for guiding water to enter the secondary pipe is fixedly connected to a position corresponding to the through hole on the inner peripheral wall of the connecting pipe, and an opening of the guide hopper faces to the end portion of the connecting pipe adjacent to the guide hopper.

By adopting the technical scheme, when water in the main pipe flows through the connecting pipe, part of water enters the auxiliary pipe under the guiding effect of the guiding hopper, the guiding hopper has the drainage effect, the flowing speed of the water in the auxiliary pipe can be accelerated, and the heat exchange efficiency is improved.

Optionally, the position rigid coupling that corresponds the through-hole on the connecting pipe periphery wall has the installation piece, set up the mounting groove with the through-hole intercommunication in the installation piece, the connector includes the articulated shell of ball joint in the mounting groove, articulated shell both ends communicate with connecting pipe and accessory pipe respectively.

By adopting the technical scheme, the auxiliary pipe can be selected with different lengths to adapt to different coverage ranges, and the included angle between the auxiliary pipe and the connecting pipe can be adjusted adaptively.

Optionally, the connector further comprises a fixing portion and a thread portion, the fixing portion is fixedly connected to the hinged shell and communicated with the hinged shell, the thread portion is fixedly connected to the fixing portion and communicated with the fixing portion, the end portion of the auxiliary pipe is rotatably connected with a buckle cap used for being in threaded connection with the thread portion, and the buckle cap is communicated with the auxiliary pipe.

By adopting the technical scheme, when the auxiliary pipe and the connecting pipe are installed, the buckle cap is screwed on the threaded part, so that the auxiliary pipe and the connecting pipe can be spliced, and the connection mode is easy for site construction operation.

Optionally, the auxiliary pipe comprises two auxiliary pipe joints, one end of each auxiliary pipe joint is connected with the corresponding connector, and a rubber hose or a metal corrugated pipe is connected between the other ends of the two auxiliary pipe joints.

By adopting the technical scheme, the length of the auxiliary pipe can be adaptively selected, the rubber hose or the metal corrugated pipe can adapt to different included angles between the two auxiliary pipes, and the rubber hose and the metal corrugated pipe have better bending performance.

Optionally, the connecting pipes on two adjacent main pipes are arranged in a staggered manner.

By adopting the technical scheme, the coverage area of the auxiliary pipe is improved, and the heat dissipation efficiency inside the concrete is accelerated.

Optionally, two adjacent main pipes are connected in series through an external pipe.

Through adopting above-mentioned technical scheme, a plurality of person in charge series connection, water is connected into by the one end of establishing ties and is responsible for, is drawn forth by another, and the diversion flow is clear, constructor only need manage and control water inlet and delivery port can, the controllability is high.

Optionally, the template is a steel template, a heat insulation board is installed in a grid of the steel template, and an iron sheet is arranged on one side of the heat insulation board, which is far away from the steel template.

Through adopting above-mentioned technical scheme, the heated board has the thermal-insulated effect of heat preservation, can effectively reduce scattering and disappearing of concrete surface temperature, reduces the inside and outside difference in temperature of concrete.

Optionally, the heat insulation layer comprises a plastic film and a heat insulation quilt.

By adopting the technical scheme, the plastic film covers the surface of the concrete, so that the water loss is reduced, and the heat preservation is reduced and the temperature loss of the surface of the concrete is reduced.

Optionally, the water injected into the heat exhaust pipeline is reservoir water.

By adopting the technical scheme, the reservoir water source is sufficient and can be taken nearby.

In summary, the present application includes at least one of the following beneficial technical effects:

1. after being injected into the heat exhaust pipeline, water enters the auxiliary pipe through the main pipe, hydration heat in the concrete is absorbed by the auxiliary pipe distributed in the concrete, and the heat carried by the water is finally exhausted from the main pipe, so that the heat in the concrete is reduced; the heat preservation layer covers the surface of the concrete, the heat loss of the surface of the concrete is delayed, and the temperature difference between the inside and the outside of the concrete is reduced in a mode of internal accelerated cooling and external delayed cooling; compared with the related technology, the method for controlling the cracks of the large-volume concrete of the arch dam can effectively solve the problem that the cracks are generated in the large-volume concrete of the dam;

2. when water in the main pipe flows through the connecting pipe, part of water enters the auxiliary pipe under the guiding action of the guiding hopper, and the guiding hopper has a drainage effect, so that the flowing speed of the water in the auxiliary pipe can be increased, and the heat exchange efficiency is improved;

3. the accessory pipe can be selected for use different length with the different coverage of adaptation, and the contained angle between accessory pipe and the connecting pipe can carry out the adjustment of adaptability.

Drawings

Fig. 1 is a flowchart of a method for controlling a large-volume concrete crack of an arch dam in embodiment 1.

Fig. 2 is an explosion diagram (not referring to an exposed end of the heat exhaust pipeline) made in order to show the matching relationship of the template, the heat insulation board and the iron sheet in embodiment 1.

Fig. 3 is a sectional view of the heat exhaust duct according to example 1, showing its components.

Fig. 4 is a schematic structural view of the connection pipe and the sub-pipe of fig. 3.

Fig. 5 is a sectional view showing the connection of the sub pipe and the connection pipe in embodiment 1.

Fig. 6 is an enlarged schematic view of a portion a in fig. 5.

FIG. 7 is a schematic view of the structure of a secondary pipe in example 2.

FIG. 8 is a schematic view of the structure of a secondary pipe in example 3.

Description of reference numerals: 1. a template; 10. a thermal insulation board; 11. iron sheet; 2. a main pipe; 20. a first flange; 3. a connecting pipe; 30. a second flange; 31. a guide hopper; 32. mounting blocks; 320. mounting grooves; 33. a connector; 330. a threaded portion; 331. a fixed part; 332. a hinged shell; 4. a secondary pipe; 40. blocking edges; 41. buckling a cap; 42. a rubber hose; 43. a metal bellows.

Detailed Description

The present application is described in further detail below with reference to figures 1-8.

The embodiment of the application discloses a method for controlling a large-volume concrete crack of an arch dam. Referring to fig. 1, a method for controlling large-volume concrete cracks of an arch dam comprises the following steps:

s1, erecting a formwork, calculating the engineering quantity of the formwork 1 according to design requirements before pouring the large-volume concrete, measuring and setting out, and then erecting the formwork 1; referring to fig. 2, in the present embodiment, the steel form is selected as the form 1, the insulation board 10 is bonded in the grid of the steel form, and the insulation board 10 in the present embodiment is a polystyrene board, which has good heat insulation performance, so as to insulate the surface of the poured concrete and delay the loss of the surface temperature of the mass concrete.

In order to protect heated board 10, still be provided with an iron sheet 11 in the heated board 10 outside, iron sheet 11 wraps up heated board 10 in 1 grid of template, and iron sheet 11 welds on 1 frame of template, carries out daily protection through iron sheet 11 to heated board 10 promptly.

And S2, binding the steel bars by constructors according to the drawing requirements after the template 1 is erected, binding and fixing the steel bars through binding wires, and performing subsequent construction after the steel bars are accepted.

S3, installing a heat exhaust pipeline, wherein the heat exhaust pipeline comprises a main pipe 2, a connecting pipe 3 and an auxiliary pipe 4 according to the figures 3 and 4; the main pipes 2 are made of steel pipes with the diameter of 40mm, each main pipe 2 is composed of three main pipe sections, a flange I20 is welded at the end part of each main pipe section, the distance between every two adjacent main pipes 2 is set to be 1.5m, and the main pipe sections are tied up and fixed on the steel bars through binding wires; two adjacent main pipes 2 are connected in series through an external connecting pipe 21, the external connecting pipe 21 in the embodiment is a rubber pipe, and the rubber pipe has better bending deformation performance.

The connecting pipe 3 is arranged between two adjacent main pipe joints, the connecting pipe 3 in the embodiment is also a steel pipe with the diameter of 40mm, two flanges 30 are welded at two ends of the connecting pipe 3, and when the connecting pipe 3 and the main pipe joints are assembled, a constructor uses the first flange 20 and the second flange 30 to be connected through bolts.

Referring to fig. 5 and 6, two sets of through holes are formed in the circumferential wall of the connecting tube 3, each set including four through holes arranged along the circumferential direction of the connecting tube 3; a guide hopper 31 is welded on the inner wall of the connecting pipe 3 corresponding to each through hole, the opening of the guide hopper 31 faces the end part of the connecting pipe 3 adjacent to the guide hopper, and the guide hopper 31 is used for guiding water in the main pipe 2 to enter the through holes; the installation block 32 is welded on the outer wall of the connecting pipe 3 at a position corresponding to the through hole, an installation groove 320 communicated with the through hole is formed in the installation block 32, and the installation groove 320 is a spherical groove.

The mounting block 32 is also provided with a connecting head 33, and the connecting head 33 comprises a threaded part 330, a fixing part 331 and a hinge shell 332; the thread portion 330 is tubular and the peripheral wall is provided with the external screw thread, the fixed portion 331 is tubular and the peripheral wall is set to regular hexagon, the fixed portion 331 is welded with the thread portion 330, the hinge shell 332 is hemispherical shell-shaped, the hinge shell 332 is spherically hinged in the mounting groove 320, the hinge shell 332 is welded at one end of the fixed portion 331 far away from the thread portion 330 and is communicated with the fixed portion 331.

The auxiliary pipe 4 is connected between two connectors 33 in different groups, the auxiliary pipe 4 in this embodiment is a bent pipe formed by bending, an annular blocking edge 40 is vertically welded on the outer wall of the end part of the auxiliary pipe 4, the end part of the auxiliary pipe 4 is also sleeved with a buckle cap 41, the buckle cap 41 is limited on the auxiliary pipe 4 through the blocking edge 40, the inner wall of the buckle cap 41 is provided with internal threads, and the buckle cap 41 is in threaded connection with the threaded part 330; referring to fig. 3, the auxiliary pipes 4 of two adjacent main pipes 2 are arranged in a staggered manner, and a constructor firstly puts the four auxiliary pipes 4 of the same connecting pipe 3 into a cross shape or other cross shapes, and then ties up and fixes the auxiliary pipes 4 on the steel bars by using binding wires.

And S4, pouring concrete, wherein the concrete is transported in a pumping mode, the cement in the concrete is selected from Portland dam cement, the concrete pumping process is continuously carried out, and the concrete is vibrated and compacted in a layered pouring construction mode.

S5, curing, namely covering a plastic film on the surface of the concrete, and covering a heat preservation quilt above the plastic film, wherein the heat preservation quilt in the embodiment is a cotton quilt, and the plastic film and the cotton quilt are used for preserving the heat of the surface of the concrete, so that the heat loss of the surface of the mass concrete is delayed.

Pumping water in the reservoir by using a water pump, filtering the water by using a filter screen before the water enters the water pump, filtering out impurities such as weeds, dry branches and the like, and connecting a water outlet of the water pump to one end of the main pipe 2 after the main pipe is connected in series; after the water pump is started, water is continuously pumped into the main pipe 2 and the auxiliary pipe 4 and is finally discharged from the other end of the main pipe 2 after being connected in series, and hydration heat in the concrete is taken out.

And S6, plugging the heat exhaust pipeline, pumping cement mortar into the heat exhaust pipeline after concrete curing is finished, and plugging the main pipe 2, the connecting pipe 3 and the auxiliary pipe 4 by using the cement mortar.

The implementation principle of the embodiment 1 of the application is as follows: the construction of the bulk concrete is carried out according to the steps S1-S6, and the auxiliary pipe 4 is in ball hinge with the connecting pipe 3, so that the spatial position of the auxiliary pipe 4 can be conveniently adjusted according to the design requirement; both ends of the connecting pipe 3 can be used as water inlets, the guide hopper 31 drains water flowing into the connecting pipe 3 into the auxiliary pipe 4, and the auxiliary pipe 4 is scattered inside the concrete, so that the heat inside the concrete is absorbed by the water more sufficiently.

Example 2

Referring to fig. 7, the present embodiment is different from embodiment 1 in that the secondary pipe 2 in the present embodiment includes two secondary pipe sections, a blocking edge 40 is disposed at one end of the secondary pipe sections, and a rubber hose 42 is connected between one ends of the two secondary pipe sections, which are far from the blocking edge 40.

The implementation principle of the embodiment 2 is as follows: firstly, two auxiliary pipe joints are arranged on the corresponding connectors 33, and then the two auxiliary pipe joints are connected by using rubber hoses 42; the auxiliary pipe sections with different lengths can be selected, so that the heat dissipation area inside concrete is changed, the heat dissipation requirements of concrete with different quantities are met, the shape and the length of the auxiliary pipe 4 are easy to adjust, the rubber hose 42 is convenient to obtain materials, and the bending performance is good.

Example 3

Referring to fig. 8, the present embodiment is different from embodiment 2 in that a metal bellows 43 is connected between ends of the two sub pipe joints away from the blocking edge 40.

The implementation principle of the embodiment 3 is that two auxiliary pipe joints are firstly installed on the corresponding connectors 33, and then the two auxiliary pipe joints are connected by using the metal corrugated pipe 43; the auxiliary pipe sections with different lengths can be selected, so that the heat dissipation area inside concrete is changed, the heat dissipation requirements of concrete with different quantities are met, the shape and the length of the auxiliary pipe 4 are easy to adjust, the metal corrugated pipe 43 is convenient to obtain, and the bending performance is good.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A method for controlling large-volume concrete cracks of an arch dam is characterized by comprising the following steps: the method comprises the following steps:

erecting a template (1) according to design requirements;

pouring concrete, pumping the concrete into the template (1), and vibrating to compact;

the heat exhaust pipeline comprises a main pipe (2), a connecting pipe (3) and an auxiliary pipe (4); be provided with a plurality ofly, every be responsible for (2) including a plurality of main tube joints, install between two adjacent main tube joints connecting pipe (3), be provided with two sets of through-holes along self length direction on connecting pipe (3) perisporium, every group includes a plurality of through-hole, the position that connecting pipe (3) perisporium corresponds the through-hole is equipped with connector (33), auxiliary pipe (4) are provided with a plurality ofly, auxiliary pipe (4) are connected between two connectors (33) that are located different groups, auxiliary pipe (4) are the arc and are fixed in on the reinforcing bar.

2. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: a guide hopper (31) for guiding water to enter the auxiliary pipe (4) is fixedly connected to the position, corresponding to the through hole, on the inner peripheral wall of the connecting pipe (3), and the opening of the guide hopper (31) faces the end part of the connecting pipe (3) adjacent to the guide hopper.

3. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: the position rigid coupling that corresponds the through-hole on connecting pipe (3) periphery wall has installation piece (32), set up mounting groove (320) with the through-hole intercommunication in installation piece (32), connector (33) are articulated hinge shell (332) in mounting groove (320) including the ball, hinge shell (332) both ends communicate with connecting pipe (3) and accessory pipe (4) respectively.

4. The method for controlling the large-volume concrete cracks of the arch dam according to claim 3, wherein the method comprises the following steps: connector (33) still includes fixed part (331) and screw thread portion (330), fixed part (331) rigid coupling on articulated shell (332) and with articulated shell (332) intercommunication, screw thread portion (330) rigid coupling on fixed part (331) and with fixed part (331) intercommunication, accessory pipe (4) tip rotates and is connected with buckle cap (41) that is used for with screw thread portion (330) threaded connection, buckle cap (41) and accessory pipe (4) intercommunication.

5. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: the auxiliary pipe (4) comprises two auxiliary pipe joints, one end of each auxiliary pipe joint is connected with the corresponding connector (33), and a rubber hose (42) or a metal corrugated pipe (43) is connected between the other ends of the auxiliary pipe joints.

6. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: the connecting pipes (3) on the two adjacent main pipes (2) are arranged in a staggered manner.

7. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: two adjacent main pipes (2) are connected in series through an external pipe.

8. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: template (1) is the steel form, install heated board (10) in the grid of steel form, one side that heated board (10) deviate from the steel form is provided with iron sheet (11).

9. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: the heat-insulating layer comprises a plastic film and a heat-insulating quilt.

10. The method for controlling the large-volume concrete cracks of the arch dam according to claim 1, wherein the method comprises the following steps: the water injected into the heat exhaust pipeline is reservoir water.